Isostasy

Summary

Isostasy is the state of gravitational equilibrium in which the Earth's crust and lithosphere float on the denser, slowly flowing mantle. In this state, at a certain depth called the depth of compensation, the weight of the overlying column per unit area is the same everywhere. Isostasy explains why high mountains have light roots and why regional Bouguer anomalies are negative over mountains. It also explains why land rises after an ice sheet melts.